Max 5 API Reference

dspstress~.c

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/**
 @file
 dspstress~ - very simple msp object that does nothing except eat up a specified % of processor time 
 
 updated 6/5/09 rbs: initial
 
 @ingroup   examples    
 */

#include "ext.h"
#include "ext_obex.h"
#include "z_dsp.h"

void *dspstress_class;

typedef struct _dspstress
{
    t_pxobject  x_obj;
    double      x_cpuusagetarget;   // how much cpu to burn (0 - 100)
    double      x_sr;               
    double      x_svs;      
    double      x_svtime_ms;        // how long one signal vector takes in ms
} t_dspstress;

void *dspstress_new(double val);
t_int *dspstress_perform(t_int *w);
void dspstress_float(t_dspstress *x, double f);
void dspstress_int(t_dspstress *x, long n);
void dspstress_dsp(t_dspstress *x, t_signal **sp, short *count);
void dspstress_assist(t_dspstress *x, void *b, long m, long a, char *s);

int main(void)
{
    t_class *c;

    c = class_new("dspstress~", (method)dspstress_new, (method)dsp_free, (short)sizeof(t_dspstress), 0L, A_DEFFLOAT, 0);
    
    class_addmethod(c, (method)dspstress_dsp, "dsp", A_CANT, 0);    // respond to the dsp message 
                                                                    // (sent to MSP objects when audio is turned on/off)
    class_addmethod(c, (method)dspstress_float, "float", A_FLOAT, 0);
    class_addmethod(c, (method)dspstress_int, "int", A_LONG, 0);
    class_addmethod(c, (method)dspstress_assist,"assist",A_CANT,0);
    class_dspinit(c);                               // must call this function for MSP object classes

    class_register(CLASS_BOX, c);
    dspstress_class = c;
    return 0;
}

void dspstress_assist(t_dspstress *x, void *b, long m, long a, char *s)
{
    if (m == ASSIST_INLET) {
        switch (a) {    
        case 0:
            strcpy(s,"Specify cpu usage % here");
            break;
        }
    }
}

void *dspstress_new(double val)
{
    t_dspstress *x = object_alloc(dspstress_class);
    dsp_setup((t_pxobject *)x,1);                   // set up DSP for the instance and create signal inlet
    x->x_sr = 0; 
    x->x_svs = 0; 
    dspstress_float(x, val); 
    return x;
}

void dspstress_float(t_dspstress *x, double f)              // the float and int routines cover both inlets. 
{                                                           // It doesn't matter which one is involved
    x->x_cpuusagetarget = f;
}

void dspstress_int(t_dspstress *x, long n)
{
    dspstress_float(x, (double) n); 
}

t_int *dspstress_perform(t_int *w)                      // our perform method 
{
    t_dspstress *x = (t_dspstress *)(w[1]);
    float spintime;
    double intime; 
    double outtime; 
    unsigned long spincounter = 0;

    if (x->x_obj.z_disabled)
        goto out;
    
    spintime = x->x_svtime_ms * x->x_cpuusagetarget / 100.; 

    intime = systimer_gettime(); 
    outtime = intime + spintime; 
    while (systimer_gettime() < outtime)
    {
        // tra la la
        spincounter++;  // how high can we count? 
    }

out:
    return (w+2);
}

void dspstress_dsp(t_dspstress *x, t_signal **sp, short *count) // method called when dsp is turned on
{
    dsp_add(dspstress_perform, 1, x);
    x->x_sr = sp[0]->s_sr; 
    x->x_svs = sp[0]->s_n;  
    x->x_svtime_ms = x->x_svs / x->x_sr * 1000.; 
}

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